| Year | Value | | 2022 | 16,555 | | 2021 | 16,638 | | 2020 | 16,766 | | 2019 | 17,011 | | 2018 | 17,365 | | 2017 | 17,782 | | 2016 | 18,190 | | 2015 | 18,507 | | 2014 | 18,697 | | 2013 | 18,763 | | 2012 | 18,729 | | 2011 | 18,640 | | 2010 | 18,430 | | 2009 | 18,062 | | 2008 | 17,592 | | 2007 | 17,033 | | 2006 | 16,425 | | 2005 | 15,824 | | 2004 | 15,263 | | 2003 | 14,741 | | 2002 | 14,281 | | 2001 | 13,907 | | 2000 | 13,623 | | 1999 | 13,427 | | 1998 | 13,313 | | 1997 | 13,260 | | 1996 | 13,231 | | 1995 | 13,195 | | 1994 | 13,132 | | 1993 | 13,066 | | 1992 | 13,027 | | 1991 | 12,905 | | 1990 | 12,630 | | 1989 | 12,312 | | 1988 | 11,988 | | 1987 | 11,624 | | 1986 | 11,209 | | 1985 | 10,748 | | 1984 | 10,268 | | 1983 | 9,784 | | 1982 | 9,292 | | 1981 | 8,762 | | 1980 | 8,170 | | 1979 | 7,568 | | 1978 | 7,003 | | 1977 | 6,471 | | 1976 | 5,962 | | 1975 | 5,477 | | 1974 | 5,030 | | 1973 | 4,657 | | 1972 | 4,379 | | 1971 | 4,175 | | 1970 | 4,014 | | 1969 | 3,885 | | 1968 | 3,777 | | 1967 | 3,674 | | 1966 | 3,567 | | 1965 | 3,461 | | 1964 | 3,369 | | 1963 | 3,283 | | 1962 | 3,195 | | 1961 | 3,100 | | 1960 | 2,979 |
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